In a large bowl, add butter, brown sugar, and granulated sugar. Using a hand mixer or stand mixer, beat until fluffy, about a minute. Add egg and vanilla extract. Beat until fluffy, about a minute.

In a separate bowl, sift together the einkorn flour, cinnamon, baking soda, and salt. Gradually stir dry ingredients into butter mixture until just combined.

Add oats and stir until just combined. Dough will feel sticky.

Cover bowl or wrap dough in wax paper. Chill for 30 minutes (up to 24 hours) in the refrigerator. Refrigerating helps the flavors meld and also creates a firmer, less sticky dough that spreads less in the oven.

Preheat oven to 350℉. Line a baking sheet with parchment paper and set aside.

Remove dough from refrigerator and scoop dough using a 1.5 tablespoon (medium) scoop or shape by hand into 1.5 inch balls.

Place cookie dough balls 2 inches apart onto a prepared baking sheet. Bake for about 12-14 minutes, or until lightly browned around edges and across the tops. Allow to cool for 5 minutes before removing to a wire rack to cool completely.